You'll most likely find these edible dark
brown mussels projecting from the mud along marsh creeks
(guts) and often among the marsh grass. Their shells are
distinguished from most other mussel shells by the ribs
that line the surfaces. Ribbed mussels are found along
most of the East Coast; those in the photo were spotted
at the edge of a gut by Toms Cove (see
map).

The mussels attach themselves with tough byssus
threads (lower photo, left side) to the marsh grass or
other solid objects in the mud. These threads are
secreted by a gland in their foot.

While many bivalves filter feed through a pair of
siphons that draw in water and then expel it, mussels do
not. When covered by the tide, mussels open slightly, and
cilia, small hairs on the gills, draw in water and the
food in it--usually algae--to the mouth.

When the tide is out, the mussels close, retaining
waste products toxic to humans. For this reason,
collecting mussels at low tide is usually avoided.